This invention relates generally to ventilation, or air exhaust, systems and concerns more specifically such systems that are easy to install, use and control at separate targeted stations of work sites and buildings.
At large work sites, such as in factories, warehouses, storage facilities, repair facilities, and the like, there is often the need to evacuate, and sometimes even to clean, contaminated air at various, particular, work and/or storage stations, while not necessarily ventilating entire work sites. For example, small storage sheds often contain materials producing dangerous fumes and therefore must be individually ventilated. Further, work stations with crushers, balers, part washers, and the like, often produce bad air containing dangerous fumes which should be evacuated to better ventilated areas, or treated locally, to protect workers at or near the stations. The needs at these various stations are diverse, and a number of different types of ventilation systems have been used in the past to provide necessary forced ventilation thereat.
For example, U.S. Pat. No. 5,499,945 to Ferlin, et al., describes a ventilation apparatus for extracting air adjacent selected work stations into a large central exhaust duct that is attached to air moving lines. In this system, there are a number of branches, each branch extending to an air inlet positioned at a suitable location adjacent to a work station. Air movers are supplied with pressurized air to produce venturi effects for sucking air from the different work stations into the central duct. Ferlin et al. points out that this system can be easily added, removed or relocated to different elevations. In one embodiment, there is a venturi connection quite near an inlet port that is supplied with pressurized air. Although this system has some flexibility, it does not provide the necessary customized control for allowing a sufficiently wide range of adjustments necessary to meet diverse situations often encountered at work sites.
U.S. Pat. No. 6,000,391 to Timmons, also describes a positive air flow ventilation system which works on venturi air flow, but which also does not provide sufficient control and structural adaptability to make it useful in the wide range of situations desired.
Other ventilation systems that have been used in the prior art include electric fans placed at exhaust holes in metal cabinets for pulling air out of the cabinets into surrounding atmosphere. One problem with such electric fans is that they cause electrical sparks that could result in igniting flammable fumes. Similarly, they must be supplied with electrical energy that also increases risk of fire.
Therefore, it is an object of this invention to provide an air exhaust system which can be easily custom installed at various stations, whose ventilation suction can be custom controlled at the stations, which does not increase the risk of fire and which provides excellent ventilation at stations by evacuating and/or cleaning their air. It is also an object of this invention to provide such an air exhaust system that is easy to mount on a wall of a housing for evacuating air from the housing.
According to principles of this invention, a vacuum air exhaust system employs a venturi vacuum pump that is fed pressurized air through a control valve unit rigidly mounted on a vacuum pump housing of the vacuum air exhaust system. By manipulating a movable valve of the control valve unit, an operator can control a vacuum applied by the vacuum pump. The vacuum air exhaust system is, in one embodiment, rigidly attached to a pipe-type mount unit having flanges and/or male threads at an intake end and to an exhaust adapter at an exhaust end. The flanges and/or male threads of the pipe-type mount unit are for engaging a wall so that ventilation suction is applied through the pipe and the wall. In one embodiment the exhaust adapter is attached to a flexible hose and in another embodiment it is rigidly screwed to a pipe, such as a filter pipe.